JPH0295711A - Relief valve of oil pump for internal combustion engine - Google Patents

Abstract

PURPOSE:To keep a circulating system at constant pressure even if the viscosity of lubricating oil varies by moving or adjusting the position of a piston, which is one of constitutive parts of a relief valve, by means of both a pressure- responded moving means and a fluid-temperature-responded moving means placed in series with the pressure-responded moving means. CONSTITUTION:An oil pump 13 is installed on a partition plate 27, which divides a chamber 26 accommodating a clutch device 25, and is driven by an inner rotor 30 that is rotated via a slave gear 15a. A cylinder part 37, which is formed between a discharge opening 35 of a boss part 27a of the partition plate 27 and a lubricating oil inlet port 36 for a counter shaft 16, is interposed with a piston 38, thereby forming a relief valve 20. In this case, the piston 38 energizes the relief valve 20 to the valve-closing-direction via a spring (pressure- responded moving means) 41, and at the same time the piston 38 energizes a spring seat 44, which encloses wax therein to the piston(38)-sliding-direction, corresponding to the temperature of lubricating oil, via a spring receiving part (temperature-responded-moving means) 42.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a relief valve for an oil pump for an internal combustion engine that can address control factors such as fluid temperature changes.

``Prior Art'' Oil pumps connected to internal combustion engines usually have a relief in order to keep the supply pressure of the oil lubrication system below a predetermined value and to prevent excessive negative pressure from being applied to the oil pump. A valve is attached.

The above-mentioned relief valve is generally
As described in Publication No. 6, a cylinder part is provided so as to communicate with the lubricating passage 71IJ near the discharge port of the oil pump, a piston is inserted into the cylinder part, and the piston is compressed and supported by a spring. It has a structure in which an escape hole is formed in the side wall. The piston is located at a location where the discharge pressure of the oil pump and the biasing force of the spring are balanced, and when the discharge pressure increases, the piston moves to open the relief hole, lowering the fluid pressure and opening the lubricating oil path. Keep the pressure below a certain level.

``Problems to be Solved by the Invention'' With the oil lubrication system using the conventional relief valve described above, problems described below may occur due to large changes in the viscosity of the lubricating oil due to temperature changes.

In other words, when the piston is pushed and the relief hole is opened as the oil pump discharge pressure increases, even if the opening area is constant, if the viscosity of the oil differs, the flow path resistance of the oil flowing from the relief hole will increase. will be different. For example, when the temperature is low and the viscosity of the oil is high, the flow path resistance is large, and conversely, when the temperature is high and the viscosity is low, the flow path resistance is small. Therefore, when the viscosity of the oil is high, the piston moves further in an attempt to open the relief hole more widely, which ultimately causes the spring to be compressed more strongly, thereby increasing the pressure in the oil lubrication system that is being adjusted. Furthermore, when the viscosity of the oil is low, the pressure in the oil lubrication system is conversely low. In other words, even though the same spring is used, if the viscosity of the oil changes as the temperature changes,
This changes the pressure in the oil lubrication system.

For this reason, if a spring is set based on low temperatures when the viscosity is high, the viscosity will be low at high temperatures and the pressure in the oil lubrication system will be lower than the required pressure. The system pressure increases and the mechanical loss of the oil pump increases. In any case, there remains some dissatisfaction with the adjustment of the oil lubrication system.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a relief valve for an oil pump for an internal combustion engine that can maintain a circulation system at a constant pressure even when the temperature of lubricating oil changes and the viscosity changes. It is something to do.

[Means for Solving the Problems] In order to achieve the object, the present invention provides a cylinder interposed between the discharge port of an oil pump driven by an internal combustion engine and the lubricating oil inlet to each part of the internal combustion engine. A piston is slidably inserted into the piston, and the fluid pressure is adjusted by moving the piston to open and close a relief hole provided in the side wall of the cylinder according to the fluid pressure acting on the piston. The relief valve for an oil pump for an internal combustion engine is characterized in that the piston is moved and adjusted by the pressure responsive means and a fluid temperature responsive means provided in series therewith.

"Operation" The movement of the piston is adjusted not only by the pressure responsive means but also by the fluid temperature responsive means, and when the viscosity of the fluid changes due to a temperature change, the piston is adjusted by the fluid temperature responsive means accordingly. You can change the opening area of the relief hole in the cylinder by changing its position.

"Example" Hereinafter, one embodiment of the present invention will be described based on the drawings.

Fig. 1 is a side view of a 4-cycle engine for a motorcycle, and in the figure, reference numeral 1 denotes 4 which is in series in the left-right direction (in the following explanation, the rear left and right sides are based on the vehicle body) and which is tilted forward.
Book cylinder 2.2 Cylinder block comprising: 3
4 is a crankcase that is integrally connected to the lower end of the cylinder block l; 4 is a cylinder head that overlaps the upper end surface of the cylinder block l and is fastened with a socket bolt 5; 6;
1 and 2 respectively show head covers that overlap and are bolted onto the upper end surface of the cylinder head 4.

The socket port for fixing the cylinder head has a special shape as shown in FIGS. 2(a) and 2(b). That is, the head of this socket bolt 5 is made longer than that normally used, and a wrench guide groove 8 is provided in the center of the two sides of the head, which is shaped like a forest and becomes narrower toward the back. The structure is such that the inner part of the guide) and ¥8 are connected to the wrench hole 9.

Since the socket bolt 5 with the guide groove is used in this way, even if the port tightening part B is at a position considerably lower than the upper end surface S of the cylinder head, as shown in FIG. Guide it and fit it into the wrench hole.
, the ease of assembly is improved. This is a great advantage not only during manual assembly and maintenance, but especially when automatic assembly is employed.

FIG. 3 shows the flow of lubricating oil in the internal combustion engine.

To explain the flow, the lubricating oil accumulated in the oil pan 11 is guided to the oil pump 13 via the oil strainer I2, and from there to the oil passages 14a and 14b to lubricate the main shaft 15 and the counter shaft 16. The oil is guided to the oil passage 14c to lubricate the crankshaft 17 and the shaft 18.

A relief valve 20, which will be described later, is attached near the discharge port of the oil pump I3.

An oil filter 21 is provided in the oil passage 14c on the side of the crankshaft 17, and the lubricating oil is purified here. The purified lubricating oil is guided to the crankshaft 17 through a predetermined oil path, and lubricates the sliding portions of the crank pin 17a and the connecting rod large end 22. Further, a portion of the engine oil is branched off before reaching the crankshaft 17, and is also guided to the exhaust camshaft +8A and the intake camshaft 18B to lubricate required locations.

The oil after lubricating the camshaft 18 is guided through the return oil path 23 to the meshing part between the crankshaft driving gear +7b and the main shaft driven gear 15a, and after lubricating this, the oil after lubricating the crankshaft 17 and the main shaft 15 is returned to the oil pan 11 together with the lubricated oil and the like.

Thereafter, the above circulation is repeated.

The oil pump 13 and the relief valve 20 will be explained in detail based on FIG. 4. In this embodiment, the oil pump I3 is of a tocoroid type, and the oil pump 13 is equipped with a transmission case 24 and a clutch device 25. A partition wall board that separates room 26? 7. A pump chamber 28 is formed in the partition plate 27, and an outer rotor 29 and an inner rotor 30 are housed inside the pump chamber 28. A cover plate 31 is fixed to the open end of the pump chamber 28 with bolts 32. The inner rotor 30 is connected to the driven gear 15a through an Oldham joint 33 passing through the center of the cover plate 31, and the oil pump 13 is operated by rotating the driven gear 15a.

The partition plate 27 has a suction port 34 that opens into the pump chamber 28.
(See Figure 3) and a discharge port 35 are drilled, and an inlet port 34 is provided.
is connected to the oil strainer I2.

On the other hand, explaining the relief valve 20, a cylinder portion 37 is formed in the boss portion 27a of the partition plate 27 between the discharge port 35 and the lubricating oil inlet 36 of the counter shaft 16. A piston 38 is slidably inserted into the holder. The cylinder portion 37 is formed with an oil escape port 39 and an air vent port 40 that allows the piston 38 to move. The cylinder portion 37
A spring (pressure responsive means) 41 is housed in the spring 41 for biasing the piston 38 in the valve closing direction with a predetermined set load. The spring 41 has one end locked to the lower end step of the piston 38, and the other end locked to the spring receiver member 42. The spring receiver member 42 further includes a locking bolt 43.
It is supported by being in contact with.

The spring receiver member 42 has a hollow structure consisting of a spring seat 44, a cap 45 fixed to the upper part of the spring seat 44, and a plunger 46 slidably fitted into the spring seat 44, and wax is sealed inside. . When the internal temperature of the member 42 increases, the wax sealed inside the spring receiver expands, causing the plunger 46 to protrude outward and move the spring seat 44 upward in the figure. When the internal temperature drops, the plunger 46
enters inward and moves the spring seat 44 downward. That is, in the bipedal spring holder member 42, the spring seat 44 moves toward the piston 3 depending on the temperature of the lubricating oil.
It will move in the sliding direction of 8.

According to this lubrication system, lubricating oil is supplied to each required part of the internal combustion engine as the oil pump 13 operates, but at this time, the discharge pressure of the oil pump 13 is regulated by the set load of the spring 41. When the pressure rises above the pressure, the piston 38 moves backward in response to the discharge pressure (see below in FIG. 4) and opens the relief hole 39, so that the excess pressure is released to the outside, and as a result, the pump discharge pressure decreases.

In addition, in the above-mentioned lubrication system, when the viscosity of the oil changes due to a temperature change, the spring retainer moves against the plunger 4 of the member 42.
6 slides to move the spring seat 44 in the direction of the sliding force of the piston 38. That is, when the temperature rises and the viscosity of the oil decreases, the wax in the spring receiver member 42 expands, causing the planter 46 to protrude and the spring seat 44 to move upward in FIG. 4. Further, when the temperature drops and the viscosity of the oil decreases, the wax in the spring receiver member 12 contracts, causing the plunger 46 to retract and the spring seat 44 to move downward.

In this way, the spring seat 4 is adjusted according to the viscosity of the lubricating oil.
4 can be moved, it is possible to compensate for changes in resistance of the oil flow path from the relief hole 39 due to changes in viscosity, thereby keeping the lubrication system constant regardless of changes in oil temperature, that is, changes in oil viscosity. Can be kept under pressure.

The type of wax sealed inside the member and the claws of the spring retainer are determined by various factors such as the type of lubricating oil used, the diameter of the cylinder portion 37, and the position of the three relief holes, etc., and are subject to temperature changes. This is determined in such a way that it is possible to correct changes in oil flow path resistance.

In the above embodiment, the movement of the spring seat 44 due to changes in the temperature of the lubricating oil is compensated for by using the spring receiver member 42, which has wax sealed inside, but this is not limited to this. The correction may be made by enclosing a material or by a member made of a shape memory alloy.

"Effects of the Invention" As explained above, according to the present invention, the movement of the piston is adjusted not only by the pressure responsive means but also by the fluid temperature responsive means, so that the viscosity of the fluid changes due to temperature changes. In this case, the opening surface of the relief hole in the cylinder portion can be changed by changing the position of the piston using the fluid temperature responsive means. As a result, the circulation system can be kept at approximately the same pressure even when the internal combustion engine is used in different environments, and even when the internal combustion engine is started and when the internal combustion engine is warmed up.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view with a part of the internal combustion engine in section, FIGS. FIG. 3 is a diagram illustrating the oil circulation system of the internal combustion engine, and FIG. 4 is a detailed diagram of the relief valve and its surroundings. 44... Spring seat.

Claims (1)

[Claims] A cylinder part that is interposed between the discharge port of an oil pump driven by an internal combustion engine and an inlet for lubricating oil to various parts of the internal combustion engine, a piston that is slidably inserted into the cylinder part, and a piston that acts on this piston. A relief valve for an oil pump for an internal combustion engine, comprising a pressure responsive means for adjusting the fluid pressure by moving the piston in accordance with the fluid pressure to open and close a relief hole provided in a side wall of the cylinder part. A relief valve for an oil pump for an internal combustion engine, characterized in that movement is adjusted by the pressure responsive means and fluid temperature responsive means provided in series therewith.